I HAVE A 2007 FORD EXPLORER 4wheel drive...i';ve been having problems rough idles for a while but not as bad as currently. (YES I recently changed fuel fliter) Well my emission light has turned one twice in the past 3days. The emission light only flashs estimated 8times than turns off. In the last 3days they have put on the scanner in hopes it gives out a code BUT NO LUCK! the weird thing is that in the past week 3 people have mention to me that my truck smells as if its overheating or an burning smell....I check coolent & its fine.... What can be the problem here? Am I at risk of being stuck in the middle of freeway? Oh yea I've notice the rough idle tends to occur only between 40mph while picking up speed once i get to 70mph it is no longer felt.

OK, i am confused. You say the problem occurs " rough idle only between 40mph while picking up speed" ?
That is not idle. Idle is sitting at an idle, a stop sign or something, not driving at 40 mph.
These are two totally different things with different possible causes.

If the light is on or flashing, there must be a trouble code stored in the computer.

I am going to guess you mean the engine is running bad at around that vehicle speed and you are accelerating? If so, this is called a missfire. This will usually be caused by a bad spark plug, ignition coil or plug wire. Since you say people mentioned a smell, this could mean a faulty EGR valve. Without knowing a trouble code, these are just basic guesses.

anyhow yes a misfire.... the light flashed about 8 times and than turned off... the second time it did it I was entering a freeway and it would not pick up speed as it if were stuck @ 40 mph mean time neither were the rpm picking up so basically as if the truck lost power.

the misfire usually takes place when entering freeways as it reaches 40 mph as well as 60 mph once i reach 70,mph the truck seems to be running perfectly FINE...

also 4 different types of scanners have been hooked up on the truck all by different people and they have all said no code is being given.... by computer is that due to the light flashing and turning back off?

No problem.
Just want to be sure what the condition is.
Normally a warning will store a code in the computer, even after the light goes off. But since you say it is the emission light, and not the check engine light, then this may just be a mileagae interval alert to needing the emissions sytem serviced and not actually related to your condition.

It does sound like an EGR or ignition problem. The problem going away after 70 MPH mean you can "Drive out of it". This seems like an EGR valve problem.

The blinking engine light on fords is strictly due to damage being detected to the catalytic converter......monitered by o2 sensors. Should be codes but you say there is none. KOEO and KOER or just saved codes? Any pending codes or pids out of value? Sounds intermittent ....I can say that the little to no acceleration is your computer shutting down cylinders in order to try and protect your cat, misfires could triger it but should also throw a code. have it looked at with a scantool that can view pids and history to see if any or many misfires occured and if they are related in some way. i recently scanned a car 03 exploder and it had over 5000 misfires it two different cylinders but no codes because it did not meet the minimum threshold of i forget but over 10000. by reading history misfires you can determine if its a cylinder miss, o2 sensor or converter. Check your converter.....and have someone monitor more than just codes a good scan tool (modis) even a genisys will tell you a lot more than you think if you know what to look for.

what kind of scanner did you use? does it have a mode 6 section? In mode 6 you can look at each cylinder for misfires. Ford has a rather large misfire threshold before it will turn on the check engine light with a stored code. but it will show up in mode 6 usually. Most people can feel the misfire before the check engine light comes on.

does the burning smell come from the engine area or from the exhaust? You may have valve cover gaskets leaking oil on the exhaust. And since it's a ford, check your PCV hoses for bad rubber elbows and connectors.

Mode 6 is great if u know what your looking at.......some, most newer fords will show misfires in live data even if its not missing at the moment. Since u said u had it checked with multiple scanners did anyone actually monitor live data? We're the o2 sensors monitored? Did they all just use a little 100$ scan tool than only reads hard/stored codes? Did anyone spend more than 10 min reading mode six data or live data, did u just plug in and see test passes no codes present and leave thinking nothing was wrong? I hate going to the dealership but to be honest they have the right tools, scan tool or computer software? Have you left your car with a mechanic so he could verify your concern? Take it to a qualified tech. And let them spend an hour or two so they have time to look it over and drive it! Better to spend 200$ than 2000$ to replace your cat and o2 along with whatever is making your car miss. Need more info at this point all I can say is the flashing light is telling you that your catalytic converter is in danger of being ruined.......not sure about your car but some fords will have 2 cats per bank so that's 4 all together......can be quite pricy to replace one or all of them.